Spider silk-inspired peptide multiblock hybrid copolymers for self-healable thin film materials

Abstract

Natural biopolymers exhibit smart functions and extraordinary physical properties because of their optimized and rational molecular structures. Understanding and mimicking such architectural principles on a nanoscale offer promising opportunities for designing novel functional polymer materials. Herein, we report unique nano/microfilm materials fabricated using spider silk-inspired peptide multiblock hybrid copolymers. The multiblock copolymers are composed of self-assembling oligopeptides (Ala, Gly, Val, and Leu-based peptides) and non-crystalline flexible polypropylene glycol. Self-supporting microfilms are easily obtained by casting from polymer solutions via β-sheet network formation, and their structural and mechanical properties are characterized comprehensively. The resulting spider silk-like specific nanostructure comprises balanced crystalline and non-crystalline regions; additionally, it exhibits reversible interactions among peptide blocks based on multiple hydrogen bonds. This enables mechanical toughness and self-healing characteristics in the thin films. Moreover, such film characteristics, including healing efficiency, can be modulated by manipulating the sequence and length of the peptide blocks. Additionally, these hybrid multiblock copolymers are used to prepare free-standing and ultraflexible nanofilms, which demonstrate excellent followability to nanoscale roughness based on film thickness and serve as a nano-coating with ion barrier function. The biomimetic approach presented herein is a facile and effective method for the development of high-performance polymer films and is promising in various fields, such as industrial, nanotechnological, and biomedical material fields.